I should probably already know this, but I want to do some photography and/or sight seeing over a medium sized city within a Class Charlie airspace. Do I need to contact them ahead of time by phone? I don't think I should just show up outside the Class Charlie and say "uh, hi there, Akron Approach, I'd like to buzz around downtown a little bit, if that's okay with you."

I have seen other Cessnas, as well as business jets, and some heavies doing this over Akron.

The location in question is Akron Ohio which I think is within KCAK Akron-Canton Regional's Class Charlie Airspace.

Most class C facilities should be accommodating right over their clearance delivery at the time of your departure, assuming the area in which you want to orbit is not within the departure or arrival corridor. Something like the following should work:

You: "Podunk Clearance, Cessna 1245C."Them: "Cessna 1245C, Podunk Clearance."You: "Podunk Clearance, Cessna 1245C is a Cessna 172 slant golf, VFR, would like to orbit over MEDIUM CITY at or below 1,500 for thirty minutes for photographs and sightseeing, with information Whiskey."

edit: Ah, sorry about that. After rereading it seems that you will be arriving into the class C from outside their airspace, not departing into it.

The above exchange should still work, only replace CLEARANCE with APPROACH and also include your current position in the response to the approach acknowledgement, as follows:

You: "Podunk Approach, Cessna 1245C is a Cessna 172 slant golf, VFR, one five miles east of PODUNK VOR at 3,500, would like to orbit over MEDIUM CITY at or below 1,500 for thirty minutes for photographs and sightseeing, with information Whiskey."